Allow `.cxx` and `.cc` extension in compile (#2273)

* Allow .cxx and .cc extensions

* Added integration test

arduino/globals/globals.go

@@ -35,6 +35,8 @@ var (
 		".hpp":  empty,
 		".hh":   empty,
 		".cpp":  empty,
+		".cxx":  empty,
+		".cc":   empty,
 		".S":    empty,
 		".adoc": empty,
 		".md":   empty,
@@ -43,11 +45,15 @@ var (
 		".ipp":  empty,
 	}
 
-	// SourceFilesValidExtensions lists valid extensions for source files (no headers)
-	SourceFilesValidExtensions = map[string]struct{}{
-		".c":   empty,
-		".cpp": empty,
-		".S":   empty,
+	// SourceFilesValidExtensions lists valid extensions for source files (no headers).
+	// If a platform do not provide a compile recipe for a specific file extension, this
+	// map provides the equivalent extension to use as a fallback.
+	SourceFilesValidExtensions = map[string]string{
+		".c":   "",
+		".cpp": "",
+		".cxx": ".cpp",
+		".cc":  ".cpp",
+		".S":   "",
 	}
 
 	// HeaderFilesValidExtensions lists valid extensions for header files

docs/platform-specification.md

@@ -172,12 +172,15 @@ These properties can be overwritten respectively with `--keys-keychain`, `--sign
 #### Recipes to compile source code
 
 We said that the Arduino development software determines a list of files to compile. Each file can be source code
-written in C (.c files), C++ (.cpp files) or Assembly (.S files). Every language is compiled using its respective
-**recipe**:
+written in C (.c files), C++ (.cpp/.cxx/.cc files) or Assembly (.S files). Every language is compiled using its
+respective **recipe**:
 
-- `recipe.c.o.pattern`: for C files
-- `recipe.cpp.o.pattern`: for CPP files
-- `recipe.S.o.pattern`: for Assembly files
+- `recipe.c.o.pattern`: for C files (.c)
+- `recipe.cpp.o.pattern`: for CPP files (.cpp/.cxx/.cc)
+- `recipe.S.o.pattern`: for Assembly files (.S)
+
+(an optional `recipe.cxx.o.pattern` and `recipe.cc.o.pattern` may be provided, if `.cxx` or `.cc` needs special
+handling, but it's not required and we do not recommend it)
 
 The recipes can be built concatenating the following automatically generated properties (for each file compiled):
 

internal/integrationtest/compile_3/compile_cxx_cc_test.go

+// This file is part of arduino-cli.
+//
+// Copyright 2022 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package compile_test
+
+import (
+	"testing"
+
+	"github.com/arduino/arduino-cli/internal/integrationtest"
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCompileSketchWithCxxOrCc(t *testing.T) {
+	// See: https://github.com/arduino/arduino-cli/issues/1149
+
+	env, cli := integrationtest.CreateArduinoCLIWithEnvironment(t)
+	defer env.CleanUp()
+
+	// Run update-index with our test index
+	_, _, err := cli.Run("core", "install", "arduino:avr@1.8.5")
+	require.NoError(t, err)
+
+	// Prepare sketchbook and sketch
+	sketch, err := paths.New("testdata", "sketch_with_cxx_cc").Abs()
+	require.NoError(t, err)
+
+	_, _, err = cli.Run("compile", "-v", "-b", "arduino:avr:uno", sketch.String())
+	require.NoError(t, err)
+}

internal/integrationtest/compile_3/testdata/sketch_with_cxx_cc/sketch_with_cxx_cc.ino

+void func_in_cc();
+void func_in_cxx();
+
+void setup() {
+    func_in_cc();
+    func_in_cxx();
+}
+
+void loop() {
+    
+}
\ No newline at end of file

internal/integrationtest/compile_3/testdata/sketch_with_cxx_cc/test.cc

+void func_in_cc() {
+    
+}
\ No newline at end of file

internal/integrationtest/compile_3/testdata/sketch_with_cxx_cc/test.cxx

+void func_in_cxx() {
+    
+}
\ No newline at end of file

legacy/builder/builder_utils/utils.go

@@ -109,6 +109,9 @@ func compileFiles(ctx *types.Context, sourcePath *paths.Path, recurse bool, buil
 	queue := make(chan *paths.Path)
 	job := func(source *paths.Path) {
 		recipe := fmt.Sprintf("recipe%s.o.pattern", source.Ext())
+		if !buildProperties.ContainsKey(recipe) {
+			recipe = fmt.Sprintf("recipe%s.o.pattern", globals.SourceFilesValidExtensions[source.Ext()])
+		}
 		objectFile, err := compileFileWithRecipe(ctx, sourcePath, source, buildPath, buildProperties, includes, recipe)
 		if err != nil {
 			errorsMux.Lock()